The field of art to which this invention pertains is the hydroprocessing of low value hydrocarbon streams to produce valuable hydrocarbon products. More particularly, the present invention is able to simultaneously desulfurize heavy vacuum gas oil and hydrocrack light cycle oil to produce desulfurized heavy vacuum gas oil, naphtha and ultra low sulfur diesel.
Petroleum refiners often produce desirable products such as turbine fuel, diesel fuel and other products known as middle distillates as well as lower boiling hydrocarbonaceous liquid such as naphtha and gasoline by hydrocracking a hydrocarbon feedstock derived from crude oil, for example. Feedstocks most often subjected to hydrocracking are gas oils and heavy gas oil recovered from crude oil by distillation. A typical gas oil comprises a substantial portion of hydrocarbon components boiling above about 315° C. (600° F.), usually at least about 50 percent by weight boiling above 315° C. (600° F.). A typical vacuum gas oil normally has a boiling point range between about 371° C. (700° F.) and about 565° C. (1050° F.).
Hydrocracking is generally accomplished by contacting in a hydrocracking reaction vessel or zone the gas oil or other feedstock to be treated with a suitable hydrocracking catalyst under conditions of elevated temperature and pressure in the presence of hydrogen to yield a product containing a distribution of hydrocarbon products desired by the refiner. The operating conditions and the hydrocracking catalysts within a hydrocracking reactor influence the yield of the hydrocracked products.
Refiners also subject distillate hydrocarbon streams to hydrodesulfurization. Although a wide variety of process flow schemes, operating conditions and catalysts have been used in commercial activities, there is always a demand for new hydroprocessing methods which provide lower costs, more valuable product yields and improved operability.